BP's shares slide after Obama rant

BP shares dipped below 400p for the first time since October 2008 as Barack Obama levelled a furious verbal assault on the beleaguered supermajor.

Harsh words: Obama has been critical of Hayward's response to the oil spill disaster

The President said he wanted to know 'whose ass to kick' over the Gulf of Mexico oil disaster and said that if BP chief Tony Hayward were in his employ he would already have been fired.

The increasingly belligerent president was asked in a TV interview about Mr Hayward's remarks that the Gulf of Mexico was 'a big ocean', 'the environmental impact is likely to be very, very modest' and that he 'wanted his life back' after being in the eye of the storm over the spill.

'He wouldn't be working for me after any of those statements,' said Mr Obama.

Frustrated at the slow progress in containing the flow of oil from the mile-deep leak, the president has been increasingly outspoken about BP and its inability to resolve the crisis since its rig exploded on April 20, killing 11 workers.

And in an ominous warning, Obama said he believed 'corner-cutting in terms of safety' may have helped pave the way towards the Deepwater Horizon disaster.

His comments will increase the pressure on Mr Hayward whose family are living in fear of reprisals over the spill after receiving threatening phone calls at their home.

Police have launched a security operation to protect Mr Hayward's wife Maureen and their two children at their isolated £1m home in rural Kent.

Mrs Hayward said the family had received several threatening phone calls and hate mail claiming to be from environmental groups. She said one letter purported to be from Greenpeace, although Greenpeace strongly denied sending any letters to the family.

Mrs Hayward said the abuse had been 'upsetting' and left them feeling 'rather uncomfortable', particularly with her husband thousands of miles away

Critics claim the devastation caused by the spill that has now spread to some of Florida's white sandy tourist beaches could seriously harm the chances of Mr Obama's Democrat Party in November's mid-term elections.

But the President insisted on NBC's Today programme that he had been on top of the calamity from the start.

A BP spokesperson said the 'door is always open' to discussions with the White House and that it has continued to make progress capturing oil from the stricken well.

BP has collected over 14,000 barrels of oil in the past 24 hours and is on track to contain 90% of the spill, possibly within days. But images of vast quantities of hydrocarbons billowing out from the well have led to scepticism over the effectiveness of its efforts.

According to US scientists BP's Deepwater Horizon well could be spewing out more than 100,000 barrels of oil a day.

Yesterday market rumours that BP could be barred from future drilling licences sent the shares tumbling below 400p, before they recovered to finish down 21.4p at 408.9p.